Carbon filter question

Hi...

I have just installed my first undergravel filter. I have had many exterior
filter units before and they have always had a carbon filter. I see that the
undergravel filter has a way to have a tube with an air pump and carbon
filter head. My question is, do I really need the carbon filter... or am I
fine without it?

Detail info
.. this is the only filter on the tank
.. freshwater
.. 29 gal
.. 3 electric blues (2.5" each)
..tank has been stable for 3 years

Thank you,
Jeff